How to find a good solar street light factory ?

With long-term survey about commercial grade solar lights , we find some characteristics about superior solar street light importer :

  1. Producing process are certificated with ISO9001-2015
  2. Factory workers are professional trained
  3. The lighting products are certificated by correlating certifications , like CE , RoHS , ETL , UL , CB , SASO , etc
  4. Selling products with warranty